Remote control system



H. G. EVERS REMOTE CONTROL SYSTEM Aug. 2, 1949.

6 Shets-Sheet 1 Filed Aug. 21, 1944 v INVENTOR.

HARRY G. EVERS wiw ATTORNEY.

Aug. 2, 1949.

H. G. EVERS REMOTE CONTROL SYSTEM fl m 6 Sheets-Shee t 3 Filed Aug. 21, 1944 E Cw E3 :3 :v 3 Fol... v n F1 Sv m H n I i t. u u n In B h n u 2. m h n u n L U u U com INVENTOR. 'HARRY G. EVERS Z M ATTORNEY.

1949' H. e. EVERS 2,477,973

REMOTE CONTROL SYSTEM Filed Aug. 21, 1944 e Sheets-Sheet 4 INVENTOR. HARRY e. EVERS Z W ATTORNEY.

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g- 1949- v H. G. EVERS v I 2,477,973

REMOTE CONTROL sis'mm -Filed Aug. 21, 1944 v v 6 Sheets-Sheet 5 FIG.5

INVENTOR. HARRY G. EVERS ATTORNEY.

Aug. 2, 1949. H. s. EVERS REMOTE CONTROL SYSTEM Filed Aug. 21, 1944 6 Sheets-Sheet 6 D INVENTOR. HARRY s. EVERS ATTORNEY Patented Aug. 2, 1949 REMOTE CONTROL SYSTEM Harry G. Evers, Chicago, 111., assignor to Automatic Electric Laboratories, Inc., Chicago, 111. a corporation of Delaware Application August 21, 1944, Serial No. 550,362

11 Claims. 1

The present invention pertains in general to Remote Control Systems and particularly to a system which employs a plurality of signaling channels to control a multiplicity of functions at a number of remote stations either simultaneously or selectively.

'The disclosure illustrating lone embodiment of the invention is used to control the operation of three aircraft, selectively or simultaneously, from a fourth control aircraft by means of a radio-frequency carrier upon which ten audio frequency signaling tones may be superimposed. It is to be understood that the invention is not limited to the control of aircraft as it will be apparent that it is readily adapted to the control of other moving vehicles or stationary equipment either by means of the radio link illustrated or by wire lines.

The principal object of the present invention is to provide a signaling system that is capable of controlling a multiplicity of functions at a rapid rate through the efficient use of a plurality of signaling channels but Without requiring the use of more than one channel at a time.

A further object of the invention is to provide a code sender for the control station having code selecting means that is common to a plurality of groups of control keys each of which controls a separate function, to provide means for allowing preferential use of the code selecting means by certain of the groups of control keys, to provide arrangements for sending codes in sequence when the key operations overlap, and to provide a novel method of initiating the operation of the code sender in response to the operation of a control key. This object is covered by a divisional application, Serial No. 627,260 bearing the same title, filed November '7, 1947.

Another object of the invention is to provide a signal receiving system in which one incoming signal channel is associated with a common control unit and in which each one of a plurality of further incoming signaling channels is associated with one of a plurality of further control units, each of the further control units being operative in conjunction with the common unit to control a, group of functions, the group selection being determined by. which one of the further channels the signals are received over and the function selection being determined 'by the chronological relationship between impulses received over the selected one of said further signaling channels and a series of impulses received over said one channel.

A still further object of the invention is to provide a signaling system for controlling a plurality of groups of functions by means of coded impulses sent over a plurality of signaling channels as in the preceding object and in which identical codes may be employed for controlling functions in different groups.

Still another object of the invention is to provide an improved signaling system for controlling a number of corresponding functions at a plurality of remote stations either simultaneously or selectively.

A feature of the invention is the attainment of the preceding objects by means of switching equipment consisting wholly of relays.

Other objects and features of the invention will become apparent upon a further perusal of the specification and the accompanying drawings, in which:

Figs. 1, 2 and 3, when placed side by side in the order named, comprise a schematic diagram of the switching equipment employed in the control plane.

Figs. 4, 5 and 6, when placed side by side in the order named, comprise a schematic diagram of the switching equipment employed in one of controlled planes.

As previously mentioned, ten audio frequency tones, any one of which may be superimposed on a radio frequency carrier, are employed to control three airplanes simultaneously or selectively. Four of these tones are used for directing the controlled planes up, down, right, or left. Two more of the tones are used for increasing or decreasing any one of ten variable functions previously selected by the switching equipment as will presently be described. The remaining four tones are used for the control of the switching equipment constituting the invention. Of the latter four tones, one is used to control a group of distributor relays in the controlled plane, and each of the other three tones controls a group of register relays in conjunction with the distributor relays. Each control signal consists of a seizure pulse of one of these three tones followed by five pulses of the tone which controls the distributor relays. During none, or any one or two, of the four spaces between the five pulses the same tone used for seizure may be repeated. The distributor relays prepare a circuit to a different one of four relays in the register corresponding to the seizure tone during each of the four spaces between the five tone pulses. When the seizure tone is repeated during these spaces the corresponding relays in the register are operated. The various combinations which can be formed by operating none, or any one or two, of the four relays permits ten functions to be controlled by a register.

In the first register four of the ten possible functions are used for plane selection and two more are used for aileron control. The second register is used for controlling five apparatus units, each of which has two possible operated conditions. I he ten possible combinations in the third register are used to prepare any two of twenty circuits associated with ten apparatus units.

Either one of the two selected circuits may thenbe completed for as long an interval ast'desired'aby the increase or decrease tone to turn on or off, or to increase or decrease the degree-of operation of, the selected one of the ten apparatus units.

The coded signals are produced in the control equipment by a relay typeucode sender'iand-ea group of ten code selecting relays. Agroup .of control keys, or switches, is provided "for each group of functions. Each key in a group corre- 'spondsto one of the code selecting relays so that the code transniittddepends upon which key in a group is operated. The same codes are used by all groups but the particular one of the three tones used for seizure and function selection'depends upon the group in which a key is operated. 'I'his' latter tone selection is accomplished by two relayg-roups, eac'h' of which is associated with one=of-"thekeygroups. These latter relay groups also cause-signals 'to be transmitted in sequence when keys in different groups are operated-at nearly the same time, and also connect the code "selecting-relays to thekey group in which a key has been operated-in order to select the code to be transmitted.

The =fuction of each unit will now be described with reference --to the accompanying drawings. In Fig. 1 the ten keys CI to CH1 which-control the ten variable functions are shown at the-top =of the-drawing. 'I'hesekeys are of the mechanical interlocking type -in--which the operation of any key releases a previously operated key-and 'latches itself operated. fleet of common'springs 'Cll 'are 'also provided and are arranged to be momentarily operated by the latching bar when any of the selecting keys is operated. The group of Tour" keys A l to A4 at 'the leftcenter portion of the drawing is'used'for plane selection. These keys are -also of the mechanical interlocking type andcommon springs A5 are 'alsoprovi'ded' for this group. ,At the 'lower'left there'is shown the in- -cr ease-decrease key "I 0 "and the quadrant switch Zll. "The'quadrant switch consists of asha'ft that "flexibly mounted near one end so .as -to nor- "mally'occupy -a vertical position, but permitting itsfree end to "be displaced forward, backward, or laterally in the same fashion as the control stick in anairplane. Four snap-action switches are positioned aboutthe shaft at 90.intervals so as topermit selective operation of any one of the .switches .by movement .of .the free end .of .the .shaft. The forward: andbackwardmotionof the .quadrant. switch operates the elevators .of-the "cont-rolled .planes, :whilethe lateral motionof :the quadrantswitchcontrolsthe rudders, either alone -or- :in conjunction with :the :ailerons :depending upon Whether a switch 21 located withinthe shaft ofthe =quadrantswitch is operated: or :released. Two. ordinary relays, 100 and 11.0, and twoi-rmeichan'ically :interlocked'rel'ays, 120 and l30,-are controlled by switch 2| to'accomplish this result :in l a manner to be described-presently. #R'elays 1'40 to Hill are storage relays-associated With'the rplane selection key group, and relays l to 4 90 are similar storage relays associated with the variable function selecting key group.

In Fig. 2 five single pole double throw toggle switches Bl to B5 are shown at the top of the 5 drawing. Each toggle switch is associated with a pair of mechanically interlocked relays like 286B and ZIBB. Each of these mechanical in- :terlockingsrelays is in iturn associated With one of the ten code selecting relays 200 to 290 shown at .10 the center of the drawing. Relay 200T shown at the left transfers the code selecting relays from the mechanically interlocked relays to contacts of the storage relays I60 and I90 of Fig. 1 when one "ofthemechanically-interlocking push keys of Fig.

' 5 ."1 is operated. "The three remaining relays 2l0S to 230s at the right of the drawing are start and ilocknutrelays which start the code sender of Fig.

3 whenever one of the code selecting relays is operated and also prevent any new codes from being registered until a previously registeredicode has 'been' transniitted.

Ihere'lays'shownin Fig.3constituting the code sender consist ofa-pair of pulsejgenerating' relays Billi -and 310, a-pulse directing relay 320, and'five counting relays 330' to 310. At the' right of the drawing a radio transmitter and'ten audio frequencyoscillators are illustrated in block form. It should be noted that although ten separate oscillators have'been illustrated for convenience, a

{to single oscillator will suffice if "it is arranged so that its frequency "is-controlled by the switching I equipment. 'This is'possible because only a-single frequency is required-at atirne and can readily be accomplished by using 'a-conventional vacuum 35 =tube oscillator in which the frequency is 'deter- 'minedby resistance 1 and capacitance, or=inductance and-capacitance elements, byproviding ten sets of frequency determining elements and connectingthe proper set "in the oscillating "circuit 1 '1) by keying relays controlled over the leads which are shown terminating in oscillators OSC. l to :OS'C. Hl.

*At the left side 'of Fig. "4 there is shown in block form theradio receiver carried by each of the y controlled plan-es which 'demodulates the signals radiated by the transmitter of Fig; 3 and applies -"'the resultant audio frequency signal to ten'band 'pass filters,' -BPF. I-td-"BPF; Ill, each of which passes the-frequency produced by its correspondso ing --osc'illator-*of Fig. 3. "The output-of each of these'filters is'used to control one of the keying relays Kl -to-K-l il. It'may be w'ell'to mention at this point 'a further advantage in using only a single audid-frequency -at a'time for signaling. In'any ampli'fyingsystem there is usually some unavoidable non-linearity 'present, such as the curvature o'f the p'late characteristic-ore. thermionic tube, which results "in cross modulation products of the signal frequencies and of their a-ha-rmonics beingpresent-in the outputof the system when more-thanone frequency is applied to the input. *These cross 'modulation products might-result in theproduction-ofa new frequency which is the same as one of the frequencies at times used' for signaling. A false operationmight be produced" by these spurious frequencies. When a single frequency isused only-harmonicsof the single frequency will be "produced by such nonlinearity in the system. False operations due to these harmonic frequencies can "be -'-avoided by using 'signal irequencies that are not harmontically related.

At the' right of Fig-: 4 are shown five distributor relays 440 to 480, a pulse directingrelay-iw'fl,

. This group of relays is common to the three registers shown in Figs. 5 and 6 and serves to suecessively prepare circuits to the relays in a register during the series of impulses constituting a signal.

Fig. 5 shows the register that is used for plane selection and aileron control. It consists of pulsing relay 500, seizure relays 5I0 and 520, register relays 530 to 550, lockout relay 510, and aileron control relay 580. The table above relays 510 and 580 shows the manner in which relay 510 is connected to the register relays in each of the three controlled planes. Relay 510 is shown connected by dotted lines as it would be connected in the first controlled plane.

The remaining two registers are shown in Fig. 6 and are similar to the first register shown in Fig. 5. The same last two digits have been used for the corresponding relays in each of the registers. The control circuits from the keying relays and from the register relays are extended to the various apparatus units by cable 80.

Returning now to Fig. 1, the transmission of a Signal to efiect a plane selection will be described in detail. As previously mentioned, plane selection is accomplished by the four key strip of interlocking push keys Al to A4. Assuming that it is desired to control plane I individually, key AI will be operated. The operation of key AI releases any previously operated key, mo-

mentarily operates the common springs A5, and

prepares a circuit to code selecting relay 220 from battery at contacts of relay 230s over lead 30, through operated contacts AI to contacts of relay I80. The momentary operation of the common springs A5 completes a circuit to relay I40 causing it to operate and lock itself by its own make contacts. Relay I40 completes a circuit to relay I50 from battery at contacts 2I IS, through contacts 22IS, over lead 3I, through contacts MI and I8I. completed only if the code selecting relays are free. If there is a code transmission in progress relays 2IOS and 22% will be operated and hence the circuit to relay I50 will not be completed until the previously registered code has been sent. 1

When relay I50 operates it closes its locking circuit to contacts of relay I40, closes a circuit to relay I60, prepares a circuit for shunting down relay I40 over lead 32, and closes a circuit to relay 2001 over lead 33. Relay I60 operates, prepares its locking circuit to lead 34, and connects all of the plane selecting keys, Al to A4, to contacts of relay 200T. Relay 200T operates; prepares its locking circuit to contacts of relay 230$; prepares a circuit to OSC. 2 from contacts of the code selecting relays over lead 45, through contacts of relay 200T to lead 35, over lead 35 to contacts of relay IE0, and thence over lead 36 to OSC. 2; and completes the connections from the plane selecting keys Al to A4, to code selecting relays 220 to 250, respectively. A circuit is thus completed to relay 220 from battery over lead 30 through contacts of key AI, contacts of relay I60, lead 31, contacts of relay 200T, through the winding of relay 220, through the chain contacts of the succeeding code selecting relays 230 to 290 to lead 38, and over lead 38 to battery, or ground, at contacts of relay 330.

The purpose of the chain contacts in the circuit last traced is to prevent more than one code selecting relay from being operated at the same time. In the present case this serves as a precaution to prevent a false code from being transmitted if two of the interlocking push keys were This latter circuit will be operated at the same time by mistake. However, as will be later described, it is intended that several of the toggle switches, BI to B5, may be operated at the same time and in that case the chain circuit causes the codes corresponding to each toggle switch operation to be sent in sequence.

Relay 220 operates over the previously traced circuit, prepares its locking circuit through relay 2IOS, closes a circuit to relay 2308, and connects lead 45 to lead 42 so as to operate OSC. I during the second spacing interval. Relay 230$ operates, removes battery from lead thus opening the operating circuit to relay 220 and removing a short circuit from relay ZIUS, and completes the locking circuit for relay 200T. Relay 2IOS operates in series with relay 220 from battery over lead 38, closes a circuit to relay 2208, closes a locking circuit to relay I60 over lead 34, removes battery from lead 3| to guard the code selecting relays, and short-circuits rela I over lead 32. Relay I40 restores and opens the looking circuit to relay I50. Relay I restores and (5183 s the operating circuits to relays I and When relay 2IOS operated it also completed a circuit to OSC. 2 from ground at contacts 3 through contacts 37L over lead 39, through contacts ZIZS and thence over the previously traced circuit including leads 45, 35, and 36 to the oscillator. The operation of OSC. 2 modulates the radio frequency carrier produced by the transmitter at a particular audio frequency. The carrier is demodulated by the radio receiver in Fig.

i 4 and the audio frequency signal causes the operation of relay K2. Relay K2 closes a circuit to relay 500 over lead 5I. Relay 500 operates, closes a circuit to relay 4!!) over lead 64, opens the locking circuit to relays 530 to 560 to release any of them which were previously operated, and closes a circuit to relay 520 from battery at contacts 50I, over lead I5, through the chain contacts of the distributor relays, over lead 70, and through contacts 502. Relay 520 operates, prepares circuits to register relays 550 and 560 from leads I3 and I4, prepares its holding circuit over lead 63 in series with relay 5I0, and prepares a circuit for extending battery to the distributor relays over lead 62 from lead 63. Relay 4I0 operates and connects battery to lead 63.

The above operations complete the registration of the code to be transmitted and the seizure of a register in the controlled plane. The code transmission is started by the operation of relay 220s which extends battery over lead 46 to the code sender. A circuit is closed to relay 3! from battery on lead :36 causing it to operate and close a circuit to relay 300. Relay 300 operates and opens the circuit to relay 3I0. Relay 3I0 restores and opens the circuit to relay 300 which restores and recloses the circuit to relay 3I0. This cycle of operations is repeated five times for each transmission of a signal as determined by counting relays 330 to Bill. The speed and the per cent closure time of the contacts of relay 3I0 is governed by the operate and release times of relays 300 and Slil. Relay 3I0 is made slow-to-release by a copper sleeve on its core. Relay 300 is made slow-to-release by an adjustable shunting resistor. Relay 3053 is also preferably made slightly slow to operate by using a relatively large number of turns in its Winding in order to secure the optimum per cent closure time of the contacts of relay BIB. During the first operation of relay 3I0, contacts 3 transfer tes,

QQE JU; he: ewe p Ql of ll: eemaletes ate rti i u relay ttia e l t ctstlz mast r -e d-hem ad-t e SG- an i chee e a I a Q era1. os ts, ett n r u t r ares a eir ui te la 59 re t j e atin i eui tar ar 33.9.; and pre ares a i feuit t a und tle si, 4.2M urlhe e nd r te et n i". elay 3J0: whenrelay 3 E3 restores the, secondtirne it, opens ng fl circuitto relay320, opens the operi et -elari d unds eed t whi hie uees t e. rer tie i o C- 2 i eeJeed 42 is connected to lead 45 by code selecting relay .29:. Subsequen pera i n atnd ester rie cause the successive operations of relays $59, 3450, and 33 0 in conjunction het petatiaa r a .20. SC- is-ope r; ated during each operation of relay ,3 I 9 and leads 43 are grounded during the :successive res; tor nstt e er' i n r a t fi ratee e lthe fth t enef relay 3 i eme ee battery from lead 38 to release relays 220; and 19 i Pl$ l h eelr-t nae ui t oun in 13 73 350 119 3J9 closes itsjown locking circuit, and connects +batte from operated contacts on elay ie t9. aunt. 9. .e1. y. ,Z;B.,$whea e ay 2! 1 Jr eteteet R a ta 70 st r R er a it. e ter eneas he ireu i o e ax- 0 fl i en h i eek ae i ai e. o ysl flfienc tl Re:

lay, 3 39 restores, Relay 220$ restores after its lew le tseaeriedend onne t tte y t a, e a ew ei tra entelbe z ne- Iheenera wn. e he re e in e 1 me tin response to the eteat eni i e i nal iltnew be described. It will be recalled that relays K2, 5.4 0., 5 0.4 M we e ope a d u lle r operat on of QSC. 2 constituting the seizure pulse. The operation of the code. sender interrupted the o era i n. i. QSQ- 2 an sed fiv succe s e operationsor QSC. I, OSC. 2 was reoperated ditriaa, the eac n i er a e wee he five: u e s- Th nterru of 056- lt rwe ab ut h l as of ela K hi h pen t e trel r t B -y tt-re o Q en the circu1t to, relay All} over lead E4, and opens the operating circuit to relay. 52iloover leads I5 and 1p thus removing ashort circuit' fromrelay Sill. Belay 5 1;; operates, prepares, circuits to relays 5 30; and. 5 ant -r n me he c n e eu e the re ister relays 53th; 55.9 'Ijhev operatiqn of QSC, I immediately after thev interruption of 059- u esh al i n Q e a K1- Whith closes a circ u it to relay 42R. Relay 4;20;operates andicloses atcircuit torelays tail and Mllliirrmulti ple, Relay 4,00,operates-andrecloses the circuit torelay MQ-mhichwas openedlby the releaseof relay- 5911 Relays 190 and 410 are, both made slow erelease by" rneansof copper sleeves oyer tn pres: ea hat he ll emain Ope ated it ri aa eeagg iteci i cilqsesacirciiitto relay can. Relay 439 operat opens the holding circuit to relay 400' which tends from lead fiZtlrrough the locking contacts 0;; re" 4ag anu contacts of relay 43 0, and prce par safcircuit to v relay 410. The succeeding s of relay 4, 20 and the distributor relays. lar to those previously described for the coun 1ng relays" of the code sender in Fig lSLT One ott he distributor relays 449} to 43B) is op er ated foreach operation of OSC. I and during the 7 four spagingintervals lead i-5 is successiyely connectepl to leads H I2 13, and M prep armg ciP tdregisterrelays 530, 540, 550, and 550; res ctitely. In this} case OSC; ZWais operated on) during the second-spacing interval, causing the operation of relays K2 and 500- during this: interval'to complete a circuitto register relay- Efliiirdrh contacts 55L over lead 15, through contactstZ-l and-the chain contacts of -the distributor relays to lead'lz; and through contacts of relay 550'; Relay 5 3E! operates, closes its locking circuit to contacts-of relay sea, and prepares a circuit to terminal The operation (if distributor relay t lii during the fifth operation of relay &2 li completes a circuit over lead 60, through contacts offrelay 516-; and through the chain con tacts Oftl}? registerrelays to terminal I. The. operationot relay 5 30 in each controlled cp depends uponthe t strapping between terminalsl, 2; 3, and E D In plane l terminal I. Will becon= nected to terminal E, as. indicated, causinghno. effect if relay E'iEi-is already restored. However, if relay 5 had previously been operated it would be lock'ed-throughl its own contacts 5.1.1. In this event-relay E'HLWiH be short-circuited by the. battery-onv terminal I causingit to release. In both planes 4 2 I and 3 vterminal i .will be connected to ternrinaliD which will cause relay 510 in those. planestobetoperatedtbyvthe battery enter-w minal. l. Relays 5:10, in planes 2 and separate, close thgfirlocking. circuits at contacts -51], open the operatingtandreleasing circuits to relays 5,81}, and remained-1 battery from, lead 65 to prevent s equ nt operations otk yine elays Ki e K!!! from having any, efiect. Until relays 5111 planesl2eand 3 aarereleasedby a subsequent oper; ation .ofithe. appropriate. ma e e n v eythe switching; equipment controls the operation. qr planeihalane. The restoration of relay tZ fl after thefiithloperat e Q O C- eonneets tt ry tq leaij-t l through co f tttttts of relay 4 46 to short: e reu t-relays 519i a d; .2 e 559M191 29 e aeeandzd seemte ea s 2 nd Ga e e a e relays Mil to Relays te et i .t itte tt f e hgglgey 42 is 'operateda s nger cycle of operations occurs except that code s e, et tgt e a 2. il he rtt d ete iq f l t 2 to be operated during the g b m1. instead or'rhesco iki. 7 ill' then bacon 1e OpQrated'in' I U causing terminal} to bacon.- eeat sit a i? ha te atir ee h ithet l etie i 9 relay 420. Relay 510 in plane 2 will therefore be short-circuited causing it to release, relay 510 in plane I will be operated, and relay 570 in plane 3 will remain operated. The contacts of keying relays K3 to KIO will therefore be effective only in plane 2.

Similarly, the operation of plane selecting key A3 disables the contacts of keying relays K3 to KIO in planes I and 2 and enables the corresponding contacts in plane 3.

Plane selecting key A4 is operated when it is desired to control all three planes simultaneously. The operations are again similar to those previously described, in this case code selecting relay 250 is operated to cause 080. 2 to be operated during both the first and second spacing intervals. Register relays 530 and 540 are thus operated causing battery to be connected to terminal E in all three planes during the fifth operation of relay 420. Relay 510 is short-circuited in each plane in which it is operated to enable the keying relay contacts in all planes. Four codes are thus used to select any one of the three planes or to select all three planes. Two more codes are used to control relay 580 as will be described. Since ten codes are available the unused contacts on the register relays could be connected to additional terminals like I, 2 and 3 andadditional keys could be added to the four key strip of keys AI to A4 to permit more than three planes to be controlled by the same equip ment. In the present disclosure the equipment is arranged to control a different function by means of the same register used for plane selection to economize on the number of relays which must be carried by each controlled plane. This additional function consists in the control of relay 500 in the selected plane, or planes, in accordance with the operation of switch 2| in the control plane.

When the quadrant switch 20 is moved forward or backward either OSC.9 or I is operated over leads 48 or 41 to cause the operation of the corresponding keying relay, K9 or KIO, in the controlled plane. Contacts on K9 or KIO operate electric motors, or other suitable means, to move the elevators in the selected plane in accordance with the operation of the quadrant switch. In a similar manner lateral movement of the quadrant switch operates OSC. 5 or 080. 6 over leads 50 or 49 to cause the operation of the corresponding keying relays, K5 or K6, in the selected plane. Contacts of K5 and K6 are connected through leads 54 and 55 to armature springs of relay 580. When relay 580 is restored leads 54 and 55 are connected to auxiliary equipment which is not shown so as to control the operation of the rudder and ailerons, but when relay 580 is operated leads 54 and 55 are connected to the auxiliary equipment so as to control the rudder alone. Normally relay 580 is restored and the combined operation of the rudder and ailerons causes the plane to bank when a turn is executed. In landing operations, switch ZI is operated to operate relay 580 so that banking will not occur when the quadrant switch is moved laterally. The transmission of a signal to' effect the operation or release of relay 580' is similar to the transmission of a plane selection signal except for the manner of registering the code in response to the operation or release of switch 2I. When switch 2| is operated it locks mechanically and closes a circuit to the upper winding of relay I00. Relay I00 operates, closes a circuit to relay IIO, closes a circuit to rel y I from battery at contacts ISI through contacts IOI and contacts of relay I20, and prepares a circuit for operating code selecting relay 200 from battery over lead 68 and through contacts of relay I20. Relay I I0 operates, prepares its locking circuit, and disconnects leads 49 and from the quadrant switch to prevent any operation of the rudder in the controlled plane while the signal is being transmitted. Relay I40 operates and closes a circuit to relay I50 from battery on lead 3I if or when the code selecting relays are free. The succeeding operations of relays I50, I00, code selecting relay 200, etc. are the same as previously described. In addition to the operations described previously the operation of relay IEO opens the operating circuit to relay M0 and closes the locking circuit to relay IE0 at contacts I6I. The operation of relay 2IOS and subsequent release of relays I40 and I50 closes a circuit to relay !30 and to the lower winding of relay I00 from battery over lead 32, through contacts of relay I50 to lead 01, through contacts of relay 200 to lead 68, and through contacts of relays I60 and I00. The

above circuit to the lower winding of relay I00 is to prevent relay I00 from being released by the opening of switch 2I during the signal transmission. Relay I 30- operates and mechanically releases relay I20. Relay I20 restores, mechanically locks relay I30 operated, and opens the operating circuit to relay I I0. When the code signal has been sent as described for the plane selecting operation relays 200 and Ellis are released by the operation of relay 330 thus removing battery from lead 68. Relay I00 remains operated as long as the circuit to its upper winding is maintained by switch 2I. Relay I39 is deenergized but is mechanically locked in the operated position by relay I20. The release of relay 2IOS also removes battery from lead 34 which releases relay I60. Relay I60 restores and unlocks relay H0 at contacts IBI. Relay IIO restores and connects leads 49 and 50 to the quadrant switch. Since none of the leads 4! to 44 are connected to lead 45 by code selecting relay and transfers leads 54 and 55 so as to enable them to control the rudder alone. Additional contacts On relay 580 transfer battery from one set of leads to another. These latter leads are used in conjunction with the circuits extended from leads 54 and 55 to eifect the desired transfer of control by the auxiliary equipment not shown. It should be noted that relay 580 will be operated only if relay 510 is restored. If plane I had previously been selected, for example, relay 580 would be operated only in plane I because relay 510 would have been operated in planes 2 and 3 by the previous plane selecting operation.

When it is desired to return to combined control of rudder and ailerons by the quadrant switch so as to execute banked turns, switch 2I is mechanically released to open the circuit to the upper winding of relay I00. Relay I00 restores, closes a circuit to relay IIO, closes a circuit to relay I40 from battery at contacts IBI, through contacts IOI and contacts of relay I30,

prepares a circuit to .toperate relay l2 -irom1Iead" 6:8, and prepares a circuit to operate code selecting1'relay2l0 from: lead-:66; Relays llil, M55, etc. operate as" before; This. time when battery is-connectedto lead 58 a circuit is closed to relay l2lls;throughv back contacts of; relay Hi0. and operated contacts of; relay I301 Relay uni! operates; opens 'the operating'circuit to'rel'ay' Hi1;

the transmitted code signal will consist of one operation ofOSC. 2' followed by five operations of 030; l with, CS0; 25 reoperatedduring'the first spacing interval. Register relay 538' will thusbecomeioperate-d causing the fifthoperati'on ofrelay' 420 to short-circuit relay 58ilifrom batteryover lead 6.0; through contacts of relay 5.1=0;3the1 chain contacts of. register relays 536 to 5.6fl11and1contacts of relay W. Relay 580 mstores; and returns leads 54i and 55 to: the joint controlaofrud'der and: ailerons; It will" be noted'tha-t'relay Etilwill be'ait'ected. only in the selected: plane, ortplanes, in'which' relay 5'! restored;

The. roperation ofv the variable function'selecting' operations by keys C'l 'to ere-isvery similar to' the plane selecting. operationsby keys Al to A4: A separate start signal register is used comprising 1 relays flEi' to 1 W0; each of which controls circuits: corresp'ond'ing'to those. controlled by the start signal register relays Mil 'to Hit; respectively, associated withi'. the planeselecting keys; Relay. l'lfllrli's operated by the momentary operat'ionrof: the common: spri'n'gsr-Cll whenever one of thekeysrCl'to-Cli! is operated to the latching position. Relay [88 is then operated over lead 31% when the code selecting relays are free. However; if'relay I til is operated; indicating that a" key in the plane selecting 'groupha-sbeen'operate'd ELIIdFthe corresponding code signal hasnot yet been transmitted, contacts 141 of-relay Md prepareiiascircuit to relay l fifl and prevent the operation of relay l8il untilthis plane selecting code has been' registered and transmitted. The plane selecting keys are thus given preference because in' using the control equipment the function selecting. key may oftentimes be operated immediately after the operation of the plane select- 1 ingkey corres-ponding to -tlie'planein which the function. is-"to be performed? When-relay lfiildoes'operate it closes a circuit to relay I99" which operates-and" connects all of the keys Cl to'Clil to'thecorresponding code selecting relays, 280 to: 290'; through" contacts-of relay 206T, which is al'sooperated by relay" l'sif 'over lead 331 The registration and transmissionof' the code signals isthesame as described for plane selection except that a greatennumber of codesare used and also that OSC. 4 'takes theplace of 03C. 2. This selection is accomplished by the operation of'relay H36 in place'or relay I 60"; thusconnecting lead fit to lead fit in' pla'ce of 'lead 35. Therefore; the first pulse of ground over lead causes the operation'of 0563. 4 which causes the-opera tion'of keying relay K K-in the controlled planes. Contact's-of relay K i' are'connected over lead 53 to the pulsing relay 1%" of the third register. Thei'register' relays 130' to 166 are successively connected to contacts of relay 165- during the corresponding four spacing intervals by the distributor relays via'lead's' iii to'1 5.

rel'aysa The complete code used is tabulatedbelow, the:- crosses indicating the spacing intervals duringswhich 65C. l is operated.

The above code is the same as chain contacts of register relays 730.to;760- are divided intotwo groups, each of whichrse'lects one of ten. circuits correspondingto thekey (Ii-to: Cit operated at the control station. Either of.

the two selected circuits can: then be'completed:

over leads 5% or 51 by the operation: of; keying: relays Kl to K8. Eitherof these'latter relaysmaybe operated by throwing key Hito. the right-or:

left to operate 08C. 1 'or 8 overleads 'lfi or 11;

As either--selected-. circuit may. becompleted for: as; long an interval as desired they are suitable: for: the control of variable functions such as? the engine throttle. This may readily be accom-- plished by providing reversible electric-motorsxfor varying the selected functions." and connecting the motors: to the leads extendingfr'om: register relays to 'lfitfso that the selected motor will run inane-direction when keying relay-K11 is erated: and sothat thezmotor will run in'jthe opt-- positedirection when keyingrelay K8 is; operated; Relay T20 'isarranged to open leads'56 and; 5T while" asignalis-being received to preventv aifalse operation in case keying relays-1K! or K8 are operated at that time; Unl'ess. this-is: done; a: momentary circuit would be completedto-an uhdesired leadif the received code requires-the op-= erationof tworegister relays because the two register relays would be operated at different times. Thefunctionscontrolled by this-register are not necessarily-variable; Auxiliary re1ays,'ar-- ranged to'be controlled over the=leads=eXtending-, from the register relays, may be provided; sothat a selected apparatus unit can.,-be-operated;by connecting. +battery to lead 56v and can-bereleased by connecting battery to lead 51.

The. transmission of code signals .in responsetothe. operation of one or more' of the .toggle switches Bl to. B5 isconsiderably differentthan-that here tofore described 7 as. regards the. registration upon thecode selecting relayss For'one" thing, it-is intended ,that anumber of these. switchesvmay be operated simultaneously or in rapid successionandthat the corresponding codes shall. then be transmitted, in succession. It is also intended that these switches may be operated. while the transmission of a code. due'to theoperationof a key in one of the other groups is. in progress. As suming that switch BI is thrown to. the right, a. circuit is closed from batteryover lead..3l, through chain contacts on relays [4'0 and I10,

At'the': conclusion of a code signal theregisterrelayslwillz beeperated in. accordance with the operations. of're'lay 10G? during the spacing intervals 'xwhi'ch" operations are controlled by the connectionsot leads 4| to M to lead 45 by the code selecting.

that used-for: planev selection. and aileron control except that. OSC. 2 was usedthen instead of CS0. 4;, The.

over lead 18, through switch Bl, contacts of relay 200B, and contacts of relay 209T to code selecting relay 2 I'll. If the code selecting relays are in use this circuit will be open at contacts 2| iS and 22 IS. If one of the keys in the other groups has been operated and has not yet been registered the circuit will also be open at contacts of relay I40 or I'll]. In the latter case the circuit will not be completed until the code selecting relays become free, the code corresponding to the operated key in the other key groups has been registered and transmitted, and the code selecting relays again become free. When the circuit is completed, relay 2!!! operates, prepares its locking circuit through relay 2IBS, closes a circuit to relay ZSQS, and closes a circuit to relay H03 in multiple with itself. Relays 230s operates. Relay 2 l B operates and mechanically releases relay 200B. Relay 200B restores and opens the operating circuit to relay 2 I 0 which also removes a short circuit from relay 2 IDS. Relay 2 HIS operates, closes a circuit to relay 2208 and removes battery from lead 3| to guard the code selecting relays and also opening the circuit to relay 2MB. The code signal is transmitted as previously described except that OSC. 3 takes the place of 080. 2. This occurs because lead 45 is connected through back contacts of relay 200T to lead 19 and relay 200T is not operated at this time. The

transmitted code thus consists of one operation 5 of OSC. 3 followed by five operations of OSC. I and a second operation of 080. 3 during the first spacing interval. The corresponding operations of keying relays KI and K3 in the controlled plane, or planes, effects the seizure of the second register by the operation of relay Elli! over lead 52 when relay K3 is operated and causes register relay 63!] to be operated during and after the signal transmission. During the fifth operation of relay 42!} a circuit is closed from battery over lead 60, through contacts of relay 6H), and through the chain contacts of the register relays 630 to 660 to the selected one of the ten leads which control the operation of auxiliary relays (not shown) to operate the corresponding apparatus unit. Auxiliary relays are used to effect a continued operation of the apparatus unit because only a momentary circuit is closed through the chain contacts of the register relays. Each auxiliary relay is preferably connected to two of the ten leads in a manner similar to the connection of relay 589 to two of the ten leads from register I so that closing a momentary circuit to one of these two leads will operate the auxiliary relay and closing a momentary circuit to the other of two leads will release the auxiliary relay. Contacts on the aum'liary relay may then be used to control an apparatus unit in accordance with the position of the corresponding switch, Bl, to B5, at the control station. When switch B! is returned to the left it closes a circuit to code selecting relay 200 from lead 18, through switch BI, and contacts of relay 2003 after any previously stored signals have been transmitted. Relay 200 operates, prepares its locking circuit through relay 2 l 33S, closes a circuit to relay 230s, and closes a circuit to relay 200B in multiple with itself. Relay 230s operates. Relay ZllllB operates, mechanically releases relay 2MB, and opens the operating circuit to relay 200 which also removes a short circuit from relay 2l0S. Relay ZIGB restores and ,mechanically locks relay 2213B operated. Relay 2|0S operates and removes battery from lead 18 by opening 14 lead 3| at contacts 2| IS. The succeeding operations will not be described as they should be apparent from the preceding description.

If all of the switches, BI to B5, were operated to the right simultaneously, a circuit would be completed to relays Zlll, 230, 250, 210, and 290 in multiple. All of these relays would attempt to operate but the operation of any one of them opens the circuit to all of the preceding code seleoing relays by means of the chain circuit connected to lead 38. Consequently, only the highest numbered code selecting relay will remain operated, in this case relay 290. The operation of relay 290 causes the operation of relay 29013, which mechanically releases relay 280B and this in turn removes the short circuit from relay 2 I 08 which removes battery from lead 3i to guard the code selecting relays and starts the code transmission. After this first code has been sent relay 2 HIS is released and battery is again connected to lead 3i. If none of the push keys CI to Clll or Al to A l have been operated in the meantime this battery is extended to lead 18 causing code selecting relays 210, 230, 250, and 210 to again attempt to operate. This time relay 2'") is the only relay which can remain operated. This cycle of operations is continued until the five codes corresponding to the operation of switches Bl to B5 to the right have been transmitted in succession. If any of the push keys is operated during the transmission of these five codes relay M0 or I'm will be operated and will extend lead 3i to relay I50 or ISO instead of to lead 18 thus causing the code corresponding to the operated push key to be registered and transmitted as soon as the code transmission in progress is completed. The transmission of the remaining codes corresponding to the operations of switches Bl to B5 will then be resumed where it was left off. Of course, some of the switches Bl to B5 may be operated to the left at the same time that others are operated to the right, the description being limited to operations in one direction merely for simplicity.

The function of relays ace and M0 in Fig. 4 was not mentioned previously because during nor mal operation they have no useful function. Relays 400 and MI] could be omitted and battery permanently connected to lead 53. The difiiculty that ma arise if this is done is that if keying relay Kl is not operated five times during the reception of a signal, due to static or some other temporary radio failure, the fifth distributor relay 440 will not be operated and consequently the re ister relays will remain connected to the distributor. The next succeedin signal will advance the distributor relays the number of steps that were missed and will then release the register relays. If the register is re-seized by a pulse of tone from OSC. 2 to :3 during one of the succeeding spacing intervals in the same signal the distributor relays will start again and will advance during the remainder of the signal. The distributor will thus remain out of step until a signal is received which has no tone pulses during the spacin intervals. The addition of relays 40B and 410 insures that the distributor relays will be restored and released from the register at the end of each transmission even when the si nal is incomplete. This is accomplished by obtaining the operating and holding battery for the distributor relays from make contacts of relay All) over leads 63 and 62. Relay M0 is operated when the register is seized and is held by relay 400 during impulsing of relay 420. At

anemone:

155 theeendoff a: signal; relays 4'0 and: 1M Ilsrelease aiiter their.slow=to releaseperiods' andrelease t'her distributor .relays and; theregister-seizure relays,-. correspondin to. relays: 51d and. 526;. ii: any of these relays remain operated due.toian--incon1-- plete or otherwise distorted signal; 7

Although the invention has been illustrated as appliedlto'remote control overaradiolink it is: 3.1501 applicable to systems Operated; over Wirelines; In a Wire system theleads whichtermr hate in oscillators 053C. l to 08C. til would' be' extended to the remote stations where theywould' control the correspondingkeying relays-'Kl to K103: In the appended claims the-term signaling; channel is intended toinclude such adirect wirer connection.

Having described and illustrated the invention, what is considered new and. is desired tosecure by--Letters Patent is pointed out in thesubjoin d claims:

What is claimed is:

l. In a selective signaling system; a sending station and a plurality of. receiving: sta tions; a signaling channel common to all offsaid:

stations; a plurality of circuits at each receiv H ing station; means at the.- sending station for transmitting station selecting or circuit: selecting codesof impulses over said signaling channel; each of, said codes comprising a fixed series. of.

current impulses of one frequency and'one or more current impulses of any one of a plurality of. other frequencies in the spaces between sue-- cessive impulses of said series; selecting means at eachreceiving station controlled by saidcodes of impulses; and lockout means. operated by the selecting means at eachreceiving station in response to a station selecting code for enabling the selection of circuits at one station, and for disabling the selection of circuits at the other stations by the selecting means in response to any circuit selecting codes received thereafter; said lockout means remaining in their respective last operated positions at eachreceiving station until resetby. the receipt of a different station; selecting code.

2. In a remote control system; a first. and a second station, a plurality of groups of circuits at the second station; means fortransmitting aseries of impulses of one type and onelor more impulses of another type interspersed between the impulses of the series, means atthe-second station for selecting any one of said circuits comprising distributing means arranged to be advancedover a plurality of selecting positionsin synchronism only with said series. of impulses transmitted by the first station and apluralityof groups of relays, a relay in each group cor-- responding to each of said selecting positionsand each group of relays being associated with one of said. groups of circuits, means for connecting any one of said groups of relays with the distributing means, and for operating the relays of such connected group in difierent-combinations in response to said other impulses which are chronologically related to the impulses. of "said series, each of saidcombinations being efiective to select a diiierent one of the circuits. in the associated group.

3. In a remote control system, a-first andra second station, a signaling channel therebe.-- tween, a plurality of circuits at the secondstation, means at the first station for transmitting a series of audio frequency impulses over said signaling channel and for transmitting other im-e pulses at any one of aplurality o..other.audio.

frequencies in one or more of the. interstices of- 1:6? saidi'series; and: meansxat thasecond'rstation: j ointly' controlled by" said'sseriesf of. impulses. anzdi. saidrotherimpulsesrror selecting any onezof said circuits as: determined: by the. numberlandii fresquencyof saidimpul'sesh 4'." In er-"selective; signaling system; awpluralityt of remotezstations, aicontrol station, meansat control. station: for transmitting a series 'of inr-y pulses of' current of. a particular frequency: tn all the remote stations; a distributor at eaclr LEI-1' mote stati'onz' operated: in response to: said series: of impulses; a series: of relays at each: remote: stationceach rendered: operative in a .particulan position of thedistributor. at thatstation', means: at the control? statl'onfor interspersin'g: either" one-ormoreimpulsesofeithenof a plurality of? other frequencies-of current. between the. inn-r pulses of'said series. and meansini. each station; operative only when: the interspersed. impulses: are of a1 :particulari'frequency to render the'.-re-'- lays' of that station: operative; andimeansz; at.- ea'chi remote. station operative by the said ine' terspersed impulses to operate a. particularirelay at: thatistatio'n dependent onth'e: numberof terspersed' impulses received, when the relays: att' that station have" been: rendered operatives.-

5;'In a selective signaling system; a. plurality of remote stations, a' control" station;:means:.-atf the control stati'on 'forv transmitting a series.;.oiiimpulses ofcurrent of. a particular frequency-to all. the .remote' stations-,1 adistri-butor-at: each' re mote station: operated" in response": to:- saidcseries oi impulses; a series of relays ateach remote: station each rendered operative ina particular: position of the distributor at that station means at-the control station for'interspersing either one; ormore impulses of either of a plurality of other frequencies of current between the 'im' pulsesof saidseries-at diiferent interstices ofsaid series of impulses, and means in each -sta-.-- tion operative only when the interspersed im-- pulses.- are of a particular frequency to renderthe: relays of that station operative, andmeans. at each. remotesta-tion operative by thesaidein terspersed impulses to" operate a particular. relay at that: station dependent on the number ofine terspersed: impulses received: and. on. the: posi tion of the interspersedimpulses relative tosaid series of impulses, when the relays at that. sta tion: have been rendered operative.

6'. In a signaling system, a-plurality of remote stations, a control station; means at saidcontroll station. for transmitting a series of impulses ofocurrent of. a particular frequency to allsaid remote stations, a distributor at each. remote.

station operated in response to said series: of; impulses,a plurality of groups of relays at each remote station, each. group corresponding to one. of a. plurality oi other frequencies, meansatsai'd remote stations for'preparinga relay in: each group for operation in each. position of each said: distributor, means at said control station for. in-.. terspersing in. the interstices of said series ofi impulses one or more impulses of current of'anyone of said plurality of other frequen'cies'to operate the'particular relays in said remote stations corresponding to the position of said-dis= tributorln each remote station and to thef-re" quency'of one or more interspersed impulses;

7. In a'signaling'system; a plurality of remote stations-,za control station; means at said control station for transmitting a series Oflll'l'lDUllSESiOf current of. a particular frequency to alFsaid'ree mote stations, adistributor at each remote-station. operated in response tosaidaseriesrofl imepulses, a plurality of groups of relays at each remote station, each group corresponding to one of a plurality of other frequencies, means at said remote stations for preparing a relay in each group for operation in each position of each said distributor, means at said control station for in terspersing in the interstices of said series of impulses one or more impulses of current of anyone of said plurality of other frequencies to operate the particular relays in said remote stations corresponding to the position of said distributor in each remote station, the frequency of said one or more interspersed impulses, and the location of the interstices of said series of impulses in which said interspersed impulses pear.

8. In a signaling system, a plurality of remote stations, a control station, means at said control station for transmitting a, series of impulses of current of a particular frequency to all of said remote stations, a distributor at each remote station operated in response to said series of irnpulses, a plurality of groups of relays at each remote station, each group corresponding to one of a plurality of other frequencies, means at said remote stations for preparing a relay in each group for operation in each position of each said distributor, means at said control station for interspersing in anyone of the interstices of said series of impulses an impulse of current of anyone of said plurality of frequencies to operate the particular relay in said remote stations corresponding to the position of said distributor in each remote station and the frequency of the interspersed impulse.

9. In a signaling system, a plurality of remote stations, 9, control station, means at said control station for transmitting a series of impulses of current of a particular frequency to all of said remote stations, a distributor at each remote station operated in response to said series of impulses, a plurality of groups of relays at each remote station, each group corresponding to one of a plurality of other frequencies, means at said remote stations for preparing a relay in each group for operation in each position of each said distributor, means at said control station for interspersing in anyone or all of the interstices of said series of impulses an impulse of current of anyone of said plurality of other frequencies to operate the particular relay in said remote stations corresponding to the position of said distributor in each remote station, the frequency of the interspersed impulse and the location of the interstices of said series of impulses in which said interspersed one or more impulses appear.

10. In a signaling system, a plurality of remote stations, a control station, means at said control station for transmitting a series of impulses of current of a particular frequency to all of said current of a particular frequency to all of said remote stations, a distributor at each remote station operated in response to said series of impulses, a plurality of groups of relays at each remote station, each group corresponding to one of a plurality of other frequencies, means at said remote stations for preparing a relay in each group for operation in each position of each said distributor, means at said control station for interspersing in anyone of the interstices of said series of impulses an impulse of current of anyone of said plurality of frequencies to operate the particular relay in said remote stations corresponding to the position of said distributor in each remote station, the frequency of the interspersed impulse and the location of the interstice of said series of impulses in which said interspersed impulse appears.

11. In a selective signalling system as in claim 1, means for unlocking said locknut frame from its preventive position at each such other station in response to a particular one of said station selecting codes, for enabling the simulta neous selection of circuits at all of said stations in response to subsequent circuit selecting codes.

HARRY G. EVERS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,832,010 Hershey Oct. 11, 1932 1,888,985 Hershey Nov. 29, 1932 1,930,525 Levy Oct, 17, 1933 1,945,470 Steeneck Jan. 30, 1934 2,082,550 Powell June 1, 1937 2,107,902 Oliver Feb. 8, 1938 2,113,368 Blodgett Apr. 15, 1938 2,141,551 Phinney Dec. 27, 1938 2,170,141 Hailes Aug. 22, 1939 2,276,646 Boswau Mar. 17, 1942 2,325,829 BosWau Aug. 3, 1943 2,339,872 Miller Jan. 25, 1944 2,394,080 Laurensen Feb. 5, 1946 

